Nearly zero energy buildings

I am sure that you would guess without difficulty what the biggest worry is for Spanish architects at the moment. The shortage of work!! That has been the main problem for the profession for the
last six years or so. But I would bet a cup of coffee with anyone that would not guess the second!!

Nearly zero-energy buildings (NZEB).

Yes, how to design NZEB. According to the Directive 2010/31UE of 19 May 2010 on
the energy performance of buildings (EPBD directive), defines in its article 2 "the buildings of nearly zero energy consumption" (Nearly Zero Energy Building, NZEB) as those "with a very high
level of energy efficiency, to be determined in accordance with Annex I".

In Spain, according to the Action Plan of energy saving and efficiency 2011-2020, the concept of building energy consumption almost 0, could be similar to a
building of class "A" in the scale of energy efficiency certificate (EPC), the definition of this concept is based on the work done so far in relation to the qualification of the energy
efficiency in buildings (energy efficiency certificates labelling) similar to the EPC´s back in the UK.

The 2010/31 directive sets, on the other hand, that from 31st of December of 2020 all new constructed buildings must be buildings of almost zero
energy consumption , anticipating this obligation to 31st December of 2018 to all buildings occupied by public administrations buildings.

Different member states are already taking measures to facilitate and even overtaking the transition of 2018-2020. Without going any further in France have set
the limit of consumption of primary energy to 50 Kw/h/m2 per year (average for the whole country) which should be applied in all residential buildings from the year 2013.

Well at the moment we architects do not know how to design such buildings and that is a fact. To carry out the final test on the building which we are suppose
to design we require a complex computer programme which has not been developed yet. This computer programme is being designed by the Ministry of Housing but as yet has not come out. There is a
beta version but I had not had the chance to get my hands on. The Murcia College of Architects have a copy but only a few people have access to it. By using this programme we can test different
construction methods and check its validity against the programme to find out if it complies with the norm or not.

From preliminary information leaked from the College of Architects it seems that for a building to comply with this NZEB regulation, we will require thermal
insulation at least 15cm thick to be inserted into the building envelope. Possibly double windows to be used and special reflecting glass to be used in South facing walls, etc.

In a nut shell those buildings must cover all their energy needs due to their design, their efficient materials and renewable sources installed in it, so it
does not emit any carbon dioxide (CO2).

Why the worry? Well, these buildings will obviously be more expensive and now when we are trying desperately to get back on our feet from the brick crisis, it
will add yet another difficulty to the building industry recovery.

It will come into force in UK from 2016.

Obviously there are advantages for these buildings in the fight against climate change and energy dependence of fossil fuels and it is so that it has convinced
the United Kingdom authorities, to put it into force, from 2016 so that all new homes must be of this type.

The basic objective of a conventional property developer is to build a home with the possible lower construction costs, that current regulation allows. In this
way, the consumption of more or less energy throughout its useful life is something secondary, which in any case that expenditure will fall on the user. Therefore, it is not striking that
buildings cause more power consumption than transport or industry, according to the American Institute of architects.

First things first. What is a zero energy building?

However, in a zero-energy housing the basic interest lies from the time the property begins to be inhabited. In this case, the main concern is with the user
spending the minimum possible energy and that this energy comes from a renewable sources of the building itself. Since they do not require fossil fuels are called also carbon zero, as it doesn´t
generate any CO2, one of the main gases that cause climate change.

However, the criteria used in the different countries in achieving energy 0 are very diverse, so there is no single definition or a standard that determines
the characteristics require that there must be a zero energy building.

The passive techniques, such as thermal insulation or solar heat or even the metabolic recycling can get that energy consumption intended to maintain the
building reduced from 70% to 90%.